What are the advantages and disadvantages of an electron microscope
Advantages:
1. High resolution, the resolution of an optical microscope is 0.2 μ m, and the resolution of a transmission electron microscope is 0.2 nm, which means that the transmission electron microscope magnifies 1000 times on the basis of an optical microscope.
2. Transmission electron microscopy is commonly used to observe fine material structures that cannot be distinguished by ordinary microscopes; Scanning electron microscopy is mainly used to observe the morphology of solid surfaces, and can also be combined with X-ray diffraction or electron spectroscopy to form electron microprobe for material composition analysis; Emission electron microscopy is used for the study of self emitting electron surfaces.
Disadvantages:
1. In an electron microscope, the sample must be observed in a vacuum, so it is not possible to observe a live sample. With the advancement of technology, environmental scanning electron microscopy will gradually achieve direct observation of live samples;
2. When processing samples, there may be structures that the samples do not originally have, which increases the difficulty of analyzing the images afterwards;
3. Due to its strong electron scattering ability, it is prone to secondary diffraction, etc;
4. Due to being a two-dimensional plane projection image of a three-dimensional object, sometimes the image is not unique;
5. Due to the fact that transmission electron microscopy can only observe very thin samples, it is possible that the surface structure of a substance is different from the internal structure of the substance;
6. Ultra thin samples (below 100 nanometers), the sample preparation process is complex and difficult, and there is damage to the sample preparation;
7. Electron beams may damage the sample through collision and heating;
8. In addition, the purchase and maintenance prices of electron microscopes are relatively high.
